Date validation against data table

Question

i am re-writing a reservation system in MVC5 using C#.  New to both.  in the DB i have a table of blackout dates. the site owner enters records in the blackout table to exclude them from selection by the visitor.

 

structure

id

startdate

enddate 

 

use case (currently)

visitor enters their arrival date

system returns the count of the entered date being between an any of the  start and end dates in the blackout table and returns validation message if the count is > 0

 

 what is the best approach to creating this validation routine in the MVC create form?

TIA